Detonator crimping device



March 20, 1956 F. R. SEAVEY ET AL DETONATOR CRIMPING DEVICE Filed April 26, 1951 n w s m 4 a m U. Y K MW 7 m 1 8 L 0 SB RM w m .1 5 9 DA 3 F hr F 9 1b Q/J/ 7 M F 1 0/0 a 4% I W. ig d z DETONATOR C '1 ENG DEVICE Application April 26, 1951, Serial No. 222,964

11 Claims. (Cl. 86-22) This invention relates to crimping devices used in the blasting an and more specifically to a compact device for crimping the tubular walls of a blasting initiator shell such as an electric detonator, into the plug which serves to close the shell containing the initiating explosives.

Heretofore, crimping of blasting initiators has been accomplished, according to one type of device, with the use of hand tools having only a pair of jaws much like pliers which crush the shell between the opposite jaws leaving discontinuities in the crimp which has the disadvantage of allowing moisture to enter the blasting initiator shell rendering it inoperable. It has been recognized that if a greater number of jaws and hence radial indentations are employed to make the crimp, a more nearly continuous and desirable crimp is obtained. Ac-

cording to one type of multi-jawed device, the crimpers are relatively cumbersome and complicated and involve a combination of many mechanical elements such as pivoted jaws, cranks, bearings, heavy frames, levers and driving plungers. These and still other prior art devices include either a pair of large jaws or a small number of jaws in excess of a pair in order to avoid the high cost of I r the precision manufacture and assembly of the extremely small parts which would be needed if a very great number of jaws were employed since the detonator shell upon which the jaws are to operate is itself a small object.

One object of EhlS invention is to provide a novel device which will produce a crimp or groove in a metal case free of the foregoing disadvantages. Another object is to provide a detonator crimper which occupies an extremely small space, and is adaptable for making a gang type of crimping apparatus suitable for mass production of blasting initiators. Another object is to provide an economical device characterized by simplicity of design and a minimum number of parts. Another object is a device capable of forming a crimp consisting of a great multiplicity of circumferential indentations thus effecting a continuous annular crimp.

Other objects will be obvious from the following description when read in connection with the accompanying drawing in which:

Fig. l is an end view of a device, illustrating one embodiment of this invention, looking at the central opening for receiving the shell to be cirmped.

Fig. 2 is an elevational view in cross-section of the device shown in Fig. 1.

Fig. 3 is a fragmentary elevational view showing a blasting initiator shell in the device of Fig. 1 during the crimping operation.

In accordance with this invention, there is provided a crimping device having a great multiplicity of diminutive crimping members in the form of turns of a compression coil spring. The spring is so arranged as to form an aperture into which the metal case to be crimped can be inserted. By compressing the coil spring while the outer periphery thereof is confined, the inner extremity of each turn of the coil of the spring is caused to flex inwardly to reduce the diameter of the aperture whereby 2,738,699 Patented Mar. 20, 1956 each of the many turns are forced to converge radially into the walls of the metal case to be crimped. Although the turns of the coil spring may be circular, polygonal, rectangular, diamond, or the like in shape, each turn of the coil is preferably flattened in shape so as to be elongated or elliptical and each is preferably disposed so that the normal tendency of the coil is for the major axis of the turns to lie at an acute angle with respect to the direction of compression of the coil spring. In such an arrangement, compression of the normally canted coil spring causes it to assume an even more flattened position and causes the inner periphery to contract about the circumference of any metal body within the aperture. If the turns of the spring are so shaped that they have no major axis lying at an acute angle to the direction of compression, for example when they are circular, the members between which compression of the spring occurs should be grooved or otherwise suitably surfaced to prevent the coil turns from falling over upon compression.

in order that the invention may be better understood, there follows a description of one embodiment of the invention with reference to the accompanying drawing of the embodiment.

The detonator crimper of this embodiment consists of an outer casing 3 having a well or circular bore 2 and within the bore a thrust cylinder 7, a pair of coil spring toroid shaped members l and 10, and a washer 11 for separating the adjacent springs from each other and to transmit thrust from spring 10 to spring 1 without entanglement of the springs. Crimping is accomplished directly by the many spaced apart turns of the continuous compression coil springs 1 and 10 arranged in tandem each concentrically within the bore 2 of the outer casing 3 which serves to confine each spring toroid to prevent radial spreading of its coils outwardly from the central axis of each toroid and its central aperture 12 adapted for reception of a detonator shell 9. The upper end of thrust cylinder 7 adjacent the coil spring members is provided with a concentric circular cylindrical recess 8 for reception of the lower portion of the detonator shell 9 which extends below and beyond the portions of the shell which are to be crimped. The working face of the outer casing 3 is provided with an end plate 4 having an opening 5 for admission of the detonator shell 9 to be crimped. The end plate 4 is fastened to the casing 3 by any suitable means such as screws 6. The part of the apertured end plate 4 which partially closes the open end of the casing bore 2 at the working face acts to support the spring members 1 and 10 within the bore against the thrust of cylinder 7.

The spring toroid l which is identical with toroid 10 consists of many turns of fine Wire of a suitable material such as steel piano wire which can be easily wound to almost any desired small diameter of coil and with a great number of closely wound turns. The spring toroid I can be formed by taking such a compression coil spring having many spaced turns of small diameters, bringing the ends of the spring together in any suitable manner to provide a continuous coil of wire Winding around a circle as an axis, and then flattening the resultant spring toroid so that each turn 13 is of elongated shape such as that of an ellipse as shown in Figs. 2 and 3. Such a spring can also be formed from a coil spring initially wound as an elliptical helix. Although an elliptical shape of coil turn is desired, any elongated turn shape with rounded extremities will be suitable provided all coil turns are substantially congruent and capable of uniform radial movement with respect to the aperture 12. Hence, the terms ellipse or elliptical as used herein are meant to be all-inclusive of such elongated coil turn shapes. The turns of the uncompressed toroidal coil 1 are canted with respect to a plane normal to the axis of the toroid in such a manner that the major axis of the ellipse of each turn normally forms an angle such as 45 with the axis of the toroid. When the coil spring is free to expand to its full axial height, each turn 13 of the coil spring 1 normally rests at this angle, at which the diameter of the aperture 12 of the coil spring toroid 1 is at a maximum larger than the diameter of the detonator shell 9 in order that the shell may pass freely into the crimping aperture 12 both before and after the crimping operation. Radial confinement by casing 3 serves to produce the desired angle of cant of the elliptical coils of an otherwise flattened spring toroid or serves to preserve the desired angle where the unconfined spring toroid normally has the desired angle of cant. Although coil spring toroid 1 and toroid may be arranged so that the upper faces adjacent the inner peripheries lie adjacent the separating ring 11 and end plate 4 respectively while the outer peripheries lie adjacent the thrust cylinder 7 and separating ring 11 respectively, it is preferred that the spring members be arranged as shown with thrust cylinder 7 bearing on the lower coil face near the inner periphery of spring toroid 1 and with separating ring 11 hearing on the face near the inner periphery of spring toroid 10. In this embodiment it is necessary that each turn 13 be elongated in shape like an ellipse and that the major axis of each intersect the central axis and form an angle less than 90 with a plane normal to the central axis of the spring toroid in order to impart maximum axial flexibility by reason of which axial thrust on the spring toroid 1 may cause the inner extremity 14 of each elongated turn 13 to flex and approach the central plane of the toroid and hence also the central axis of the aperture 12' of the spring toroid 1. The result is to move each coil turn extremity 14 into the aperture 12 thereby contracting the aperture and causing the coil turns to press into the side walls of the detonator shell to provide a series of closely spaced indentations, effectually a continuous annular crimp. In effect the inner extremities 14 of the coil turns 13 provide a great multiplicity of crimping fingers in a converging radial array about the circular aperture 12 of the spring toroid 1 and of each additional spring 10. When more than one annular crimp is desired, there is disposed within the bore 2 of the casing 3 a corresponding number of such springs such as 1 and 10 in tandem and between each adjacent pair of coils an apertured separating ring 11. The function of ring 11 as pointed out hereinbefore is to prevent entanglement of the crimping springs and to transmit thrust between the springs. If only one crimp is desired, spring 10 and separating washer 11 are omitted.

In order to actuate the coil spring members 1 and 10 to accomplish the crimping operation, there is provided a thrust member in the form of a hollow circular cylinder 7, slidably and rotatably disposed within the circular bore 2 of the casing 3. The end of the inner cylinder 7 adjacent the coil spring toroid 1 is provided with a concentric circular recess 8 of depth and diameter suitable for reception of the lower portion of a detonator shell 9 inserted in the device for the crimping operation. The opposite end of the cylinder 7 carries a wedge cam 15 adapted to engage with a mating wedge cam 16 carried by the casing 3 and disposed within the bottom of the casing well 2. Rotation of cylinder 7 witlrrespect to the casing 3 causes earns 15 and 16 to either engage or disengage, thereby respectively either forcing the cylinder 7 against the crimping springs 1 and 10 or allowing the cylinder 7 to drop away from the crimping springs.

In order to actuate the thrust cylinder 7, there is provided any suitable means such as a lever 17 fastened to the lower portion of the cylinder and passing through a slot 18 in the casing 3 adjacent the bottom of the casing well 2. When the device is intended for manual use, there is provided another lever 19 fastened to the casing 3 and operation is obtained by moving lever 17 with respect to lever 19, which merely serves to support and 4 hold case 3 while cylinder 7 is actuated. The thrust cylinder 7 may be provided with any other suitable actuating means such as a hydraulic ram or a spur gear engaging with a rack or the like.

In order to axially confine the spring toroid 1 within the casing when axial thrust is applied by cylinder 7, the end of the bore 2 of the casing 3 adjacent the working face of the casing is provided with an apertured end plate 4 fastened to the casing 3. The opening 5 in the end plate 4 is of a diameter sufiicient to pass a detonator shell into and out of the casing.

To crimp a detonator shell 9 with the use of the device of this invention, the shell 9 is inserted through opening 5 in end plate 4 to occupy the recess 8 in the hollow thrust cylinder 7 and central apertures 12 of both crimping springs. T he depth of the recess 8, with respect to the length of the detonator shell 9, is such that the springs 1 and 18 are positioned with respect to the part of the shell protruding from recess 8 to provide on actuation a pair of annular grooves in the shell at the desired location about the upper plug portion of the shell. The device is actuated by movement of levers 17 and 19 with respect to each other to cause rotation of thrust cylinder 7 with respect to the outer casing 3. Cams 15 and 16 are thereby caused to engage and force cylinder 7 toward end plate 4 as rotation of cylinder 7 with respect to case 3 occurs. Axial movement of cylinder 7 toward end plate 4 subjects coil spring toroid 1 and toroid 10 to axial compression between the recessed end of thrust cylinder 7, separating ring 11, and the aperturcd end plate 4. As each spring toroid is flattened axially by the force exerted on'it, the inner extremity 14 of each elliptical coil turn 13 of springs 1 and 10 moves radially into that portion of the side wall of the detonator shell 9 in the central aperture 12 of each toroid accomplishing the crimping operation as is shown in Fig. 3. Following reverse movement of levers 17 and 19, cylinder 7 drops away from the crimping coils 1 and 10 allowing each turn 13 of these coils to relax away from the shell 9 which has been crimped thereby freeing the crimped shell for removal from the device.

While in the foregoing embodiment a device suitable for forming annular crimps and utilizing coil springs arranged in toroidal shape is set forth in detail, it is to be understood that the device of this invention may be likewise utilized to provide segment-like, spiral, or other types of crimp it only being necessary to so arrange the spring or springs and compression members about the aperture to provide the desired design of crimp.

By means of this invention, there is provided a very simple and compact crimping device all parts of which can be inexpensively manufactured. Because of the dura bility of the coil spring, the device has the advantage of long life-without need for repair. Another advantage secured by the invention is the provision of a high quality annular crimp. A still further advantage is that the device involves no minute working parts such as pivoted jaws, the manufacture of which requires a high degree of manufacturing skill and precision.

Although the foregoing specific embodiment has been set forth in considerable detail, it is to be understood that many modifications and changes may be made therein without departing from the spirit and scope of this invention as set forth in the appended claims.

What is claimed and desired to secure by Letters Patent is:

1. .A device for circumferentially crimping a detonator shell or .the like comprising a coil spring in the form of a toroid-adapted to be coaxially arranged about a detonator shell and having a multiplicity of spaced elliptical coil turns radially arrayed about the central-aperture of said toroid with the major axis of each of said turns canted with respect to the central axis of said toroid at the same acute angle; a coaxial casing embracing the outer periphcry of said coil spring toroid for radially confining said toroid; means in contact with said toroid adjacent the outer periphery thereof for supporting said toroid axially; means for axially compressing said spring toroid within said casing against said axial support means whereby all of said elliptical turns are caused to roll together inwardly contracting the central aperture of said toroid to crimp said detonator shell disposed within said aperture.

2.v A device for circumferentially crimping a detonator shell or the like comprising a continuous coil spring in the form of a toroid adapted to be coaxially arranged about a detonator shell and having a multiplicity of spaced elliptical coil turns radially arrayed about the central aperture of said toroid with the major axis of each of said turns uniformly canted out of the central plane of said toroid at an acute angle; a coaxial casing embracing the outer periphery of said coil spring toroid to radially confine said toroid; means in contact with one face of said toroid adjacent the outer periphery thereof for supporting said toroid axially; a hollow cylinder slidably disposed within said coaxial casing and adapted to receive said detonator shell and to flatten said coil spring toroid against said axial support means whereby all of said elliptical turns are caused to roll together inwardly and become flattened to contract said central aperture of said toroid and produce a crimp about said detonator shell disposed within said aperture.

3. A device for circumferentially crimping a detonator shell or the like comprising a casing having a circular bore; radially embraced within the bore of said casing,

a coil compression spring toroid having a multiplicity of spaced elliptical turns, the major axis of each of said turns forming an angle with a plane normal to the axis of said toroid and passing through a point on the central axis of said toroid; an end plate carried by one end of said casing for axially supporting said toroid within the bore of said casing, said end plate having an aperture coaxial with the bore of said casing for admission and extraction of said detonator shell; a thrust cylinder slidably and rotatably disposed within the bore of said casing, one end of said cylinder contiguous with said coil spring toroid having a coaxial recess for reception of said detonator shell and the opposite end of said thrust cylinder provided with wedge cam members adapted in association with mating wedge cam members carried by said casing to cause said cylinder when subjected to rotation with respect to said casing to thrust said toroid against said axial support means for said toroid, whereby the inner extremities of said elliptical coil turns of said toroid are caused to converge radially into the walls of said detonator shell to provide a substantially continuous annular crimp about the circumference thereof.

4. A device for circumferentially crimping a detonator shell or the like comprising a coil spring toroid having a multiplicity of spaced elliptical turns the major axes of which pass through a point on the central axis of said toroid out of the central plane of said toroid; a casing having a circular bore coaxially arranged about said coiled spring toroid; means carried by said casing apertured for admission and extraction of said detonator shell and adapted for contacting one face of said coil spring toroid to axially support said toroid within the bore of the casing; means for axially compressing said coil spring toroid against said axial suport means; and means for actuating said crimping means.

5. A device for providing a substantially continuous annular crimp about the circumference of a detonator shell or the like comprising a casing having a circular bore; coaxially arranged in tandem within said bore a plurality of coil spring members each in the form of a toroid having a multiplicity of spaced elliptical turns arranged to converge radially and form an acute angle between the major axis of each of said turns and the central axis of said toroid; an apertured separating member coaxially disposed in the bore of said casing between each adjacent pair of said spring members; means in contact coaxially disposed within said tendem arrangement of.

spring members.

6. A device for providing a substantially continuous annular crimp about the circumference of a detonator shell or the like comprising a compression coil spring ar ranged as a toroid and having a multiplicity of spaced elliptical turns each canted with respect to the central plane of said toroid so that the major axis of each of said coil turns passes through a point on the central axis of said toroid and forms an angle of approximately with respect to said central plane of said toroid; a casing concentrically disposed about the outer periphery of said toroid to prevent outward radially spreading of said toroid; means in contact with one face of said toroid adjacent the outer periphery thereof for axially supporting said toroid within said casing; and thrust means in contact with the other face of said toroid adjacent the inner periphery thereof for compressing said toroid between said axial support and said thrust means whereby the inner extremity of the major axis of each of said coil turns is urged into registry with the central plane of said toroid, and the central aperture of said toroid is caused to contract.

7. A device for providing a substantially annular crimping about the circumference of a detonator shell or the like comprising a continuous coil spring having a multiplicity of closely spaced elongated turns radially arrayed as a toroid about a circular aperture adapted for reception of a detonator shell to be crimped; a coaxial casing embracing the outer periphery of said coil spring toroid to resist outward spreading of said toroid and to give the centrally converging major axis of each of the turns of said toroid a cant with respect to a plane normal to the axis of said central aperture; means to axially support one side of said coil spring toroid within the bore of said casing; and means for axially compressing said coil spring toroid against said axially support means, whereby the normally dilated circular aperture of said coil spring toroid is caused to contract about the circumference of said detonator shell within the aperture and produce an annular crimp about said detonator.

8. A device for providing a substantially annular crimp about the circumference of a detonator shell or the like comprising a continuous coil spring having a multiplicity of closely spaced elliptical turns radially arrayed as a toroid about a circular aperture adapted for reception of a detonator shell to be crimped, a hollow casing embracing and radially compressing said coil spring toroid within the bore of said casing in order to cant the converging major axes of the elliptical turns of said coil spring toroid at an acute angle with respect to a plane normal to the axis of said toroid; means for axially supporting one side of said coil spring toroid within the bore of said casing; and means in the bore of said casing in contact with the other side of said spring coil toroid for axially compressing said toroid, whereby that the major axis of each of the elliptical turns of said toroid are forced into a position more nearly normal to the circular axis of said toroid to cause a contraction of the circular aperture of the toroid about a detonator shell contained therein sufdcient to produce an annular crimp about said detonator shell.

9. A device for crimping articles comprising a helical coil having a multiplicity of turns, means for supporting said coil with each of its turns in tangential contact on one side outside vof the confines of each of said turns with the article to be crimped; means ,for confining the other side portion of each turn opposite the article to be crimped and means for laterally compressing said coil to cause its turns on said one side to indent said article.

l0.'A device for crimping articles annularly compris-' ing a coiled-coil crimping element having primary turns each adapted to be put into contact on a side outside of the confines of said primary turns with an annular surface of said article, means for radially confining the other side portion of each primary turn opposite the article to be crimped, and means movable in lateral contiguity with said turns for compressing said coiled-coil element causing the individual primary turns thereof to indent said.

article annularly.

11. A ,device ,for circumferentially crimping articles comprising a double helical coil spring with a circular axisand with the shape of toroid having an inner diameter approximating the'exte'mal diameter of the articleto be.

crimped and defining an orifice for'receptionof said article, means for radially confining the outer periphery of said spring opposite thezobjectto be crimped, andmovable means for acting compressively :on said spring 'in the References Cited in the file ofthis patent UNITED STATES PATENTS 1,879,663 Dreyer Sept. 27, 1932' 2,050,230 Mantle Aug. 4, .1936 2,284,259 Burkhardt May 26, 1942 2,483,659 1949 Miller 'Oct. 4, 

